<!DOCTYPE html>
<html lang="zh-CN">
<head>
  <meta charset="UTF-8">
  <title>上传视频</title>
  <style>
    body { text-align: center; font-family: sans-serif; }
    form { margin-top: 50px; }
    input[type=file] { margin: 20px 0; }
    input[type=submit] { padding: 8px 16px; }
  </style>
</head>
<body>
  <h1>上传要跟踪的视频</h1>
  <form method="post" enctype="multipart/form-data">
    <input type="file" name="file" accept="video/*" required><br>
    <input type="submit" value="上传并开始跟踪">
  </form>
  <p><a href="{{ url_for('index') }}">返回</a></p>
</body>
</html>
